Portable battery



FIG. 1 is a front, top perspective view of a portable battery of our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a left-hand side view thereof;

FIG. 5 is a right-hand side view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof; and,

FIG. 8 is a back, bottom perspective view thereof.

The broken line portions of the figure drawings are included to show unclaimed subject matter only and form no part of the claimed design. 

CLAIM The ornamental design for a portable battery, as shown and described. 